Adhesive composition, rubber reinforcement material and article

Abstract

The present application relates to an adhesive composition comprising a naturally occurring acid, a nitrogen compound, and a latex; and rubber reinforcements and articles comprising the adhesive composition.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Korean Patent Application No. 10-2020-0173509 filed on December 11, 2020, and Korean Patent Application No. 10-2021-0158503 filed on November 17, 2021, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference in their entirety.

[0003] The present application relates to an adhesive composition, a rubber reinforcement material (eg, a cord), and an article (eg, a tire). Background Art

[0004] Fiber reinforcements are used to enhance the strength of rubber structures. For example, polyester fibers, polyamide fibers, aromatic polyamide fibers, and polyvinyl alcohol fibers are used as reinforcements for rubber tires. Furthermore, since some fibers may have poor adhesion to rubber, applying an adhesive to the fiber surface can improve the adhesion between the rubber and the fiber. For example, an adhesive is applied to the polyester fibers used in tire cords (raw cords) to improve adhesion with the rubber used in tires.

[0005] In the prior art, resorcinol-formaldehyde (RF) or components derived therefrom are commonly used as adhesives for these applications. However, RF, which contains resorcinol (a phenol) and formaldehyde (a known carcinogen), is harmful to the human body, and the waste adhesive containing RF incurs additional costs for post-management and post-processing.

[0006] On the other hand, as the method that adhesive composition is applied to fiber reinforcement material, dipping or spraying can be considered.In the cord manufacturing process of application said method, each component constituting adhesive composition must be uniformly mixed and dispersed in the solvent contained in the composition.In addition, it is important that, even after dipping or spraying each component by uniformly mixed and dispersed composition, appropriate composition can be uniformly applied to the surface of fiber reinforcement material (such as original cord).This is because, if the component constituting adhesive composition is not fully mixed, or if the mobility of composition becomes too high because of using excessive solvent etc., then can not ensure bonding force.

[0007] Therefore, there is a need for a technology that provides physical properties equal to or better than prior art products (such as adhesives, cords and / or tires) while being less harmful to the human body and environmentally friendly, and which can provide improvements such as process convenience. Summary of the Invention

[0008] Technical issues

[0009] One object of the present application is to provide an adhesive that is less harmful to the human body and is environmentally friendly.

[0010] Another object of the present application is to provide an adhesive that, when used, can provide physical properties equal to or superior to those of prior art adhesives.

[0011] Another object of the present application is to provide an adhesive having excellent adhesive force.

[0012] Another object of the present application is to provide an adhesive that can provide process convenience during the adhesive coating process.

[0013] Still another object of the present application is to provide a reinforcing material (eg, a cord) manufactured by using the adhesive and an article (eg, a tire) including the reinforcing material.

[0014] The above-mentioned objects and other objects of the present application can be fully achieved through the present application described below.

[0015] Technical Solution

[0016] According to the present disclosure, provided are an adhesive composition comprising a naturally occurring acid (or natural acid), a nitrogen compound, and latex, and satisfying a predetermined viscosity; a rubber reinforcement material comprising a coating of the adhesive composition and a fiber cord; and an article comprising the rubber reinforcement material.

[0017] As used herein, the term "room temperature" refers to a temperature in a state where no temperature reduction or temperature increase is particularly performed, and may refer to, for example, a temperature in the range of 15°C to 30°C. Specifically, within the above temperature range, the room temperature may be a temperature of 17°C or higher, 19°C or higher, 21°C or higher, or 23°C or higher, and may be a temperature of 29°C or lower, or 27°C or lower. In addition, unless otherwise specifically stated herein, the temperature at which numerical performance evaluation is performed may be room temperature.

[0018] Unless otherwise defined herein, the term "solid content" may refer to the amount of active ingredient (which may be in solid form) remaining after evaporating the moisture or liquid component (e.g., solvent) of the composition or each component contained in the composition. The conditions for evaporating the moisture or liquid component (e.g., solvent) are not particularly limited, but for example, warm (heating) conditions within the range of 70°C to 100°C for about 0.5 to 3 hours may be applied.

[0019] Hereinafter, an adhesive, a rubber reinforcing material, and an article manufactured using the adhesive, etc. according to specific embodiments of the present application will be described.

[0020] In an exemplary embodiment of the present application, the present application relates to an adhesive composition comprising a naturally occurring acid, a nitrogen compound, and latex.

[0021] In the prior art, adhesive compositions for tires typically contain a resorcinol-formaldehyde (RF) component. However, the present inventors have developed an adhesive composition containing a naturally occurring acid to address issues related to the harmful effects of using resorcinol-formaldehyde (RF) on the environment or human body. As demonstrated in the test examples described below, the adhesive composition of the present application containing a naturally occurring acid component has the following advantages: compared to the prior art using RF, it is not only harmless and environmentally friendly, but also can provide performance equal to or higher than the prior art during use and provides convenience in processing.

[0022] As used herein, the term "naturally occurring acid" is a term used to distinguish it from an artificially synthesized acid component, and it can refer to an acid from a plant and / or microorganism, or an acid comprising a material from a plant and / or microorganism. For example, a naturally occurring acid can be a component extracted from the bark, oak galls or leaves of a plant. More specifically, plants such as Mimosa wattle (Acacia mollissima), Schnopsis sp and Pinus radiate contain a large amount of tannins, and this plant can be used to extract naturally occurring acid. This naturally occurring acid can be, for example, an aromatic compound with a hydroxyl group, that is, a phenolic or polyphenolic compound.

[0023] In one exemplary embodiment, the naturally occurring acid may be, or may include, naturally occurring tannic acid. Tannic acid is an aromatic compound having a phenolic hydroxyl group and is known to contain gallol units and / or catechol units. Furthermore, this tannic acid may be a mixture of various naturally occurring substances, including plants.

[0024] Since the naturally occurring acid as described above has an aromatic structure containing hydroxyl groups, it can provide the composition with appropriate aggregation through hydrogen bonding and / or hydrophobic bonding. In addition, as described below, it can provide a color (color difference or chroma) unique to the cord.

[0025] In an exemplary embodiment, the naturally occurring acid may have Figure 6 The infrared absorption peak characteristics shown in FIG, which will be described below. Specifically, when analyzed by infrared spectroscopy, the naturally occurring acid can show an infrared absorption peak at 1650 cm -1 The absorption peaks are at the following wave numbers.

[0026] like Figure 6 As shown in Figure 2, unlike naturally occurring tannic acid, synthetic tannic acid exhibits a peak at approximately 1707 cm -1 The absorption peak at a wavenumber corresponding to C=O bonds is observed. This is believed to be because the synthetic tannic acid process produces more C=O units than naturally occurring tannic acid. The presence of many C=O bonds increases affinity for water, making adhesives containing synthetic tannic acid thinner than adhesives containing the same amount of naturally occurring tannic acid. This can hinder the viscosity characteristics described below. Furthermore, the color difference demonstrated between the Examples and Comparative Example 3 described below is believed to be due to structural differences confirmed by infrared absorption peak analysis.

[0027] In one embodiment of the present application, the adhesive composition satisfies a relative viscosity (RV) measured at room temperature using an Ubbelohde viscometer within a range of 2.30 or more and 3.00 or less.

[0028] "Relative viscosity" refers to the ratio of the viscosity (characteristic) of a composition to the viscosity (characteristic) of a reference solvent, and the reference solvent for measuring the relative viscosity may be water (e.g., demineralized water or pure water). Specifically, relative viscosity (RV) can be calculated by measuring the time (T1) required for the composition to pass through a predetermined scale segment of an Ubbelohde viscometer and the time (T0) required for water (e.g., demineralized water) to pass through a scale segment of the same size, and then dividing T1 by T0. The relative viscosity calculated from T1 and T0 measured by the same viscometer under the same conditions can be treated as a dimensionless constant (or dimensionless value). More specifically, the relative viscosity will be treated as a dimensionless constant (or dimensionless value) in conjunction with the following reference to Figure 1 Describe the experiment to give a description.

[0029] Specifically, the lower limit of the relative viscosity may be, for example, 2.31 or more, 2.32 or more, 2.33 or more, 2.34 or more, 2.35 or more, 2.36 or more, 2.37 or more, 2.38 or more, 2.39 or more, 2.40 or more, 2.41 or more, 2.42 or more, 2.43 or more, 2.44 or more, 2.45 or more, 2.46 or more, 2.47 or more, 2.48 or more, 2.49 or more, 2.50 or more, 2.51 or more, 2.52 or more, 2.53 or more, 2.54 or more, 2.55 or more, 2.56 or more, 2.57 or more, 2.58 or more, 2.59 or more. When the relative viscosity is less than the above range, there is a problem that the low molecular weight polymer formed during the preparation and curing process of the composition is transferred to the adherend and the adhesive force is reduced, thereby failing to provide sufficient performance (e.g., mechanical strength, etc.) for the intended use. In addition, when the relative viscosity is lower than the above range, the fluidity is relatively large, and thus, a sufficient coating cannot be formed on an adherend.

[0030] In addition, the upper limit of the relative viscosity of the composition can be, for example, 2.99 or less, 2.98 or less, 2.97 or less, 2.96 or less, 2.95 or less, 2.94 or less, 2.93 or less, 2.92 or less, 2.91 or less or 2.90 or less, more specifically, 2.89 or less, 2.88 or less, 2.87 or less, 2.86 or less, 2.85 or less, 2.84 or less, 2.83 or less, 2.82 or less, 2.81 or less, 2.80 or less, 2.79 or less, 2.78 or less, 2.77 or less, 2.76 or less, 2.75 or less, 2.74 or less, 2.73 or less, 2.72 or less or 2.71 or less. When the relative viscosity exceeds the above range, the cohesive force between the high molecular weight polymers formed during the production and / or curing of the composition becomes large, and the adhesive becomes difficult to be evenly distributed (or applied) on the adherend, thereby causing a problem of reduced adhesion. Therefore, sufficient performance (for example, mechanical strength, etc.) for the intended use cannot be provided.

[0031] As a result, as shown in the following test examples, the adhesive composition satisfying the above relative viscosity range provides excellent adhesive force, and improves processability and productivity in the manufacture and application of the adhesive.

[0032] The above-mentioned viscosity can be obtained by, for example, appropriately adjusting the components and contents of the adhesive composition described below.

[0033] In an exemplary embodiment, based on the total content of 100 % by weight composition, the composition can include the naturally occurring acid of more than 1.0 % by weight. Corresponding content can refer to the solid content occupied by naturally occurring acid in the composition. Specifically, the lower limit of the content of naturally occurring acid can be, for example, more than 1.5 % by weight, more than 2.0 % by weight, more than 2.5 % by weight, more than 3.0 % by weight, more than 3.5 % by weight, more than 4.0 % by weight, more than 4.5 % by weight, more than 5.0 % by weight, more than 5.5 % by weight or more than 6.0 % by weight. And, the upper limit can be, for example, less than 15 % by weight, less than 14 % by weight, less than 13 % by weight, less than 12 % by weight, less than 11 % by weight, less than 10 % by weight, less than 9 % by weight, less than 8 % by weight, less than 7 % by weight, less than 6 % by weight or less than 5 % by weight. When meeting above-mentioned content, advantageously provide the viscosity and the adhesiveness of appropriate level for adhesive.

[0034] In an exemplary embodiment, the naturally occurring acid can be mixed with other composition components in a dispersed state in a solvent (water or an organic solvent). In this case, the content and type of the solvent for dispersing the naturally occurring acid component can be determined within the range that can satisfy the viscosity of the above-mentioned entire composition.

[0035] The nitrogen compound is used to adjust the acidity of the composition containing tannic acid. Specifically, the nitrogen compound adjusts the acidity of the composition containing tannic acid to exhibit stable adhesive properties.

[0036] The specific type of the nitrogen compound can be selected from a level that does not interfere with the function of the above-mentioned nitrogen compound.For example, the nitrogen compound can include at least one selected from ammonia (NH3), aniline, trimethylamine, methylamine, dimethylamine and ethylamine.

[0037] In one exemplary embodiment, the composition may include at least 0.5% by weight of the nitrogen compound based on 100% by weight of the total composition content. The corresponding content may refer to the solid content of the composition accounted for by the nitrogen compound. Specifically, the lower limit of the nitrogen compound content may be, for example, at least 1.0% by weight, at least 1.5% by weight, or at least 2.0% by weight. The upper limit may be, for example, at most 5.0% by weight, at most 4.5% by weight, at most 4.0% by weight, at most 3.5% by weight, or at most 3.0% by weight. When the above content is met, it is advantageous to ensure stable adhesive properties by adjusting the titratable acidity.

[0038] In an exemplary embodiment, the nitrogen compound may be mixed with other composition components in a dispersed state in a solvent (water or an organic solvent). In this case, the content and type of the solvent used to disperse the nitrogen compound component may be determined within a range that satisfies the viscosity of the entire composition.

[0039] The latex component is a component used in consideration of the purpose of the composition. Specifically, the adhesive composition can be used to strengthen an adherend such as a rubber composite or a rubber reinforced material, and the latex can advantageously ensure compatibility, miscibility, or adhesion with the adherend. In some cases, the latex component included in the adhesive composition can be selected to be the same as the rubber component forming the adherend.

[0040] Unless contrary to the present application, there is no particular limitation on the type of latex that can be used in the composition, as long as it can meet the above-mentioned viscosity of the entire composition.

[0041] In one exemplary embodiment, the latex that can be used includes natural rubber latex, vinyl-pyridine latex (hereinafter referred to as "VP latex") such as vinyl-pyridine-styrene-butadiene copolymer latex, styrene-butadiene copolymer latex, acrylate copolymer latex, butyl rubber latex, chloroprene rubber latex or modified latex thereof. Regarding the modified latex, there is no limitation on the method of modifying the latex and the specific type of latex. For example, a modified latex obtained by modifying a vinyl-pyridine-styrene-butadiene copolymer with a carboxyl group or the like can be used.

[0042] Commercially available latexes can be used as long as they do not violate the present application, such as satisfying the viscosity of the overall composition described below. For example, commercially available VP latexes include LM-60 from Denaka, VP-150 from APCOTEX, VB-1099 from Nippon A&L, 5218 from Closlen, and 0653 from Closlen.

[0043] In an exemplary embodiment, a latex component including at least one of the above-described latexes may be used in the adhesive composition.

[0044] In an exemplary embodiment, the latex can be mixed with other composition components in a state of being dispersed in a solvent (water or an organic solvent). In this case, the content and type of the solvent used in the latex component can be determined within the range that can satisfy the viscosity of the above-mentioned entire composition.

[0045] In an exemplary embodiment, based on the total content of the composition, the adhesive composition can include the latex of more than 5 % by weight. In this case, the content can refer to the content occupied by the latex solid content in the composition. Specifically, the lower limit of the content of latex can be, for example, more than 6.0 % by weight, more than 7.0 % by weight, more than 8.0 % by weight, more than 9.0 % by weight, more than 10.0 % by weight, more than 11.0 % by weight, more than 12.0 % by weight, more than 13.0 % by weight, more than 14.0 % by weight, more than 15.0 % by weight, and the upper limit can be, for example, below 30 % by weight, below 25 % by weight, below 20 % by weight or below 15 % by weight. When meeting the above range, it is advantageous to ensure that the compatibility, miscibility and / or the bonding force of the rubber adherend containing the adhesive are used therein.

[0046] In an exemplary embodiment, the adhesive composition may include 5 to 50 parts by weight of a naturally occurring acid component based on 100 parts by weight of the latex. For example, the lower limit of the content of the naturally occurring acid can be, for example, 6 parts by weight or more, 7 parts by weight or more, 8 parts by weight or more, 9 parts by weight or more, 10 parts by weight or more, 11 parts by weight or more, 12 parts by weight or more, 13 parts by weight or more, 14 parts by weight or more, 15 parts by weight or more, 16 parts by weight or more, 17 parts by weight or more, 18 parts by weight or more, 19 parts by weight or more, 20 parts by weight or more, 21 parts by weight or more, 22 parts by weight or more, 23 parts by weight or more, 24 parts by weight or more, 25 parts by weight or more, 26 parts by weight or more, 27 parts by weight or more, 28 parts by weight or more, 29 parts by weight or more, 30 parts by weight or more, 31 parts by weight or more, 32 parts by weight or more, 33 parts by weight or more, 34 parts by weight or more, 35 parts by weight or more, 36 parts by weight or more, 37 parts by weight or more, 38 parts by weight or more, 39 parts by weight or more, or 40 parts by weight or more. In addition, the upper limit of the content of the naturally occurring acid may be, for example, 49 parts by weight or less, 48 ​​parts by weight or less, 47 parts by weight or less, 46 parts by weight or less, 45 parts by weight or less, 44 parts by weight or less, 43 parts by weight or less, 42 parts by weight or less, 41 parts by weight or less, 40 parts by weight or less, 39 parts by weight or less, 38 parts by weight or less, 37 parts by weight or less, 36 parts by weight or less, 35 parts by weight or less, 34 parts by weight or less, 33 parts by weight or less, 32 parts by weight or less, 31 parts by weight or less. Parts by weight or less, 30 parts by weight or less, 29 parts by weight or less, 28 parts by weight or less, 27 parts by weight or less, 26 parts by weight or less, 25 parts by weight or less, 24 parts by weight or less, 23 parts by weight or less, 22 parts by weight or less, 21 parts by weight or less, 20 parts by weight or less, 19 parts by weight or less, 18 parts by weight or less, 17 parts by weight or less, 16 parts by weight or less, 15 parts by weight or less, 14 parts by weight or less, 13 parts by weight or less, 12 parts by weight or less, 11 parts by weight or less, or 10 parts by weight or less. When the above range is met, stable adhesive performance can be ensured, and a viscosity suitable as an adhesive for tire cord can be obtained.

[0047] In an exemplary embodiment, the adhesive composition may include 0.5 to 25 parts by weight of the nitrogen compound based on 100 parts by weight of the latex. For example, the lower limit of the content of the nitrogen compound may be, for example, 1.0 parts by weight or more, 1.5 parts by weight or more, 2.0 parts by weight or more, 2.5 parts by weight or more, 3.0 parts by weight or more, 3.5 parts by weight or more, 4.0 parts by weight or more, 4.5 parts by weight or more, 5.0 parts by weight or more, 5.5 parts by weight or more, 6.0 parts by weight or more, 6.5 parts by weight or more, 7.0 parts by weight or more, 7.5 parts by weight or more, 8.0 parts by weight or more, 8.5 parts by weight or more, 9.0 parts by weight or more, 9.5 parts by weight or more, 10.0 ... .5 parts by weight or more, 11.0 parts by weight or more, 11.5 parts by weight or more, 12.0 parts by weight or more, 12.5 parts by weight or more, 13.0 parts by weight or more, 13.5 parts by weight or more, 14.0 parts by weight or more, 14.5 parts by weight or more, 15.0 parts by weight or more, 15.5 parts by weight or more, 16.0 parts by weight or more, 16.5 parts by weight or more, 17.0 parts by weight or more, 17.5 parts by weight or more, 18.0 parts by weight or more, 18.5 parts by weight or more, 19.0 parts by weight or more, 19.5 parts by weight or more, or 20 parts by weight or more. In addition, the upper limit of the content of the nitrogen compound may be, for example, 24.5 parts by weight or less, 24.0 parts by weight or less, 23.5 parts by weight or less, 23.0 parts by weight or less, 22.5 parts by weight or less, 22.0 parts by weight or less, 21.5 parts by weight or less, 21.0 parts by weight or less, 20.5 parts by weight or less, 20.0 parts by weight or less, 19.5 parts by weight or less, 19.0 parts by weight or less, 18.5 parts by weight or less, 18.0 parts by weight or less, 17.5 parts by weight or less, 17.0 parts by weight or less, 16.5 parts by weight or less, 16.0 parts by weight or less, 15.5 parts by weight or less, 15.0 parts by weight or less, 14.5 parts by weight or less, 14.0 parts by weight or less, 13.5 parts by weight or less, 13.0 parts by weight or less, 12.5 parts by weight or less, 12.0 parts by weight or less, 11.5 parts by weight or less, 11.0 parts by weight or less, 10.5 parts by weight or less, 10.0 parts by weight or less, 9.5 parts by weight or less, 9.0 parts by weight or less, 8.5 parts by weight or less, 8.0 parts by weight or less, 7.5 parts by weight or less, 7.0 parts by weight or less, 6.5 parts by weight or less, 6.0 parts by weight or less, 5.5 parts by weight or less, 5.0 parts by weight or less, 4.5 parts by weight or less, 4.0 parts by weight or less, 3.5 parts by weight or less, 3.0 parts by weight or less, 2.5 parts by weight or less, 2.0 parts by weight or less, 1.5 parts by weight or less, or 1.0 part by weight or less. When this content range is met, stable adhesive performance can be ensured by adjusting the acidity.

[0048] In an exemplary embodiment, the adhesive composition may further include a solvent. The solvent component included in the adhesive may refer to a component other than the above-mentioned other components, and the content of the other components may be measured as solid content. For example, the solvent component may be referred to as a non-solid content component.

[0049] The solvent may include, for example, at least one selected from known organic solvents and water. Known organic solvents are not particularly limited, and examples thereof include toluene and ethanol.

[0050] In an exemplary embodiment, the solvent component in the adhesive composition may include water or may be water.

[0051] In addition, in a specific embodiment of the present application, the adhesive composition may include water instead of an organic solvent (such as toluene or ethanol) as a solvent component, taking into account the harmfulness to the human body and flammability. Alternatively, an excess of water and a small amount of an organic solvent may be used as the solvent of the adhesive composition.

[0052] In an exemplary embodiment, the content of the solvent in the adhesive composition can be 35% by weight or more, 40% by weight or more, 45% by weight or more, 50% by weight or more, 55% by weight or more, 60% by weight or more, 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, or 90% by weight or more, based on the total weight of the adhesive composition. In addition, the upper limit of the content of the solvent can be, for example, 95% by weight or less, 90% by weight or less, 85% by weight or less, 80% by weight or less, 75% by weight or less, 70% by weight or less, 65% by weight or less, 60% by weight or less, 55% by weight or less, or 50% by weight or less.

[0053] In an exemplary embodiment, the solvent included in the content range may be water or may include water.

[0054] In another exemplary embodiment, excess or most of the solvent content can be occupied by water. For example, the excess solvent component content in the composition (e.g., based on the gross weight of the adhesive composition, about 35% by weight or more or 40% by weight or more) can be water, and the remaining content in the solvent other than water (e.g., based on the gross weight of the adhesive composition, 30% by weight or less, 25% by weight or less, 20% by weight or less, 15% by weight or less, 10% by weight or less, or 5% by weight or less) can be occupied by an organic solvent or the like.

[0055] In an exemplary embodiment, the adhesive composition can be a water-based composition or an aqueous composition. Specifically, the solvent can include an excess of water and a small amount of an organic solvent. Alternatively, the solvent can be water.

[0056] Although not particularly limited, the water used as a solvent in the adhesive composition may be demineralized water (or pure water, demineralized water).

[0057] In an exemplary embodiment, the water content may be 35% by weight or more, 40% by weight or more, 45% by weight or more, 50% by weight or more, 55% by weight or more, 60% by weight or more, 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, or 90% by weight or more, based on the total weight of the composition whose viscosity is measured. In addition, the lower limit of the water content may be, for example, 95% by weight or less, 90% by weight or less, 85% by weight or less, 80% by weight or less, 75% by weight or less, 70% by weight or less, 65% by weight or less, 60% by weight or less, 55% by weight or less, 50% by weight or less, or 45% by weight or less.

[0058] In an exemplary embodiment, the content of the solvent in the entire composition may refer to the content of water mixed as a solvent.

[0059] In another exemplary embodiment, it may also mean that the content of the solvent in the entire composition includes not only the content of water mixed as a solvent, but also the content of the solvent (e.g., organic solvent and / or water) used to disperse the solid content components, for example, as in the case where a latex dispersed in a solvent is mixed with other components to form a composition.

[0060] When the content of the solvent is less than the above range, the dispersibility and miscibility of the various components forming the composition deteriorate, coating processability deteriorates, and the adhesive force of the adhesive layer formed on the adherend decreases. Furthermore, when the content of the solvent exceeds the above range, it is difficult to form an adhesive layer on the adherend, thereby failing to fully demonstrate the desired properties of the rubber reinforced material or rubber composite material. Furthermore, when the content of the solvent exceeds the above range, processing performance is poor and production costs increase due to the need for extended drying time.

[0061] In an exemplary embodiment, the adhesive composition may further include a small amount of a known adhesive (composition) component known in the art related to tires or tire cords. In this case, a small amount may mean that the adhesive is included in the composition in an amount less than the most commonly used component among the latex component, the acid component, and the nitrogen compound. Alternatively, a small amount may mean that the adhesive is included in the composition in an amount less than the least commonly used component among the latex component, the acid component, and the nitrogen compound.

[0062] As known adhesive components that can be used, for example, isocyanate, epoxy resin, urethane, or various additives can be mentioned. Specific types of compounds such as isocyanate, epoxy resin, and urethane can be selected at a level that does not violate the achievement of the technical purpose of the present application, and the content can also be used in a small amount at a level that does not violate the achievement of the technical purpose of the present application.

[0063] In an exemplary embodiment, the adhesive composition can be formed by mixing a solvent with other components except the solvent. Specifically, in a specific embodiment of the present application, the adhesive composition can be a mixture of naturally occurring acid, nitrogen compound, latex and solvent. Or, the adhesive composition can be a mixture of naturally occurring acid, nitrogen compound, latex, solvent and known adhesive components. For example, the composition comprises more than 35 % by weight, more than 40 % by weight, more than 45 % by weight, more than 50 % by weight, more than 55 % by weight, more than 60 % by weight, more than 65 % by weight, more than 70 % by weight or more than 75 % by weight, and the solvent (non-solid component) of 85 % by weight or less or 80 % by weight, and can comprise the same solid content as the remaining residue amount. In addition, other components except the solvent, i.e. the solid content component can be, for example, less than 40 % by weight, less than 35 % by weight, less than 30 % by weight or less than 25 % by weight, and more than 15 % by weight or more than 20 % by weight. Or, the solid component of above-mentioned content and the solvent (non-solid component) of residual amount can form composition.

[0064] In one embodiment related to the present application, the adhesive composition does not contain resorcinol-formaldehyde (RF) or components derived therefrom. That is, the composition of the present application can be an RF-free composition. Thus, an adhesive composition that is harmless to the human body and environmentally friendly, compared to prior art techniques using RF components, can be provided. Furthermore, the use of such an adhesive composition offers the advantage of reduced post-management and post-processing costs.

[0065] In a specific embodiment of the present application, the adhesive composition may not include a colorant (color-imparting agent or dye).

[0066] Generally, the fiber that is used to form cord has white color, and the adhesive that is applied to the fiber is transparent.In addition, when transparent adhesive composition is applied to the tire cord fiber (or fiber base material) of white, it is necessary to confirm whether adhesive composition is fully and evenly applied (or coated) to the degree that can guarantee the required performance of tire cord, but it is not easy to confirm the coating degree of the transparent adhesive that is applied on white fiber.In this respect, in the prior art, by including colorant in the adhesive component and confirming the color of the cord that has been coated with adhesive, confirm whether fully coating adhesive.However, because colorant acts as so-called nucleating agent according to the condition of movement or storage of adhesive, it has improved the viscosity of whole composition.The viscosity of adhesive improves the coating performance that has reduced adhesive, and this causes the bond strength relevant to cord to reduce and other performance deterioration relevant to bond strength.

[0067] On the other hand, according to the present application, as described in the test below, since a naturally occurring acid component is used that can impart color difference values ​​(L, a, and b values) within a predetermined range to the tire cord, it is possible to easily and conveniently confirm the extent to which the adhesive has been applied to the tire cord fiber (or fabric substrate) (e.g., whether sufficient and uniform application has been achieved). This saves time and money. Furthermore, a tire cord that has been sufficiently and uniformly coated with adhesive has the advantage of providing superior performance compared to a tire cord that has not been sufficiently and uniformly coated with adhesive.

[0068] In another exemplary embodiment of the present application, the present application relates to a rubber reinforcement material. The rubber reinforcement material can be, for example, a tire cord having the above-described adhesive coated on a substrate. The substrate can be a raw tire cord containing a fiber component.

[0069] Specifically, the rubber reinforcement material (e.g., tire cord) may include: a raw cord containing fibers; and a coating formed on the raw cord. The coating may be a coating formed from the adhesive composition, or may include the adhesive composition, and may be applied in a shape surrounding the surface of the raw cord.

[0070] The original cord can be or include a textile formed by twisting filament fibers. In a specific embodiment of the present application, the original cord can be formed by twisting (e.g., primary twisting and / or secondary twisting) one or more fibers (e.g., multifilament). For example, the original cord can be two or three strands of cord.

[0071] The fibers contained in the raw cord are not particularly limited, and examples thereof may include at least one selected from polyester fibers (eg, PET fibers), nylon fibers, aramid fibers, carbon fibers, polyketone fibers, cellulose fibers (eg, lyocell fibers, rayon fibers), and glass fibers.

[0072] In an exemplary embodiment, the original cord may be a hybrid cord. For example, the original cord may be a hybrid cord formed by secondary twisting of primary twist yarns having different types of fibers (such as primary twist yarns of aramid and primary twist yarns of nylon).

[0073] In the case of hybrid cords formed by secondary twisting of different types of primary twist yarns, fatigue resistance is reduced due to differences in properties (e.g., modulus, etc.) between the primary twist yarns, thereby deteriorating tire stability. However, since the above-mentioned adhesive composition not only forms a suitable coating on the hybrid primary cord as an adherend but also imparts excellent adhesion between the hybrid primary cord as an adherend and the adjacent tire components, it is expected that the problem of deterioration in tire fatigue resistance caused by the use of hybrid cords can be improved to a certain extent.

[0074] In an exemplary embodiment, the twist count of the fiber bundle for forming the original cord in the primary twisting and / or secondary twisting can be more than 150 and less than 900TPM (twist per meter). For example, the twist count can be more than 200TPM, more than 250TPM, more than 300TPM, more than 350TPM, more than 400TPM, more than 450TPM, more than 500TPM or more than 550TPM. In addition, the upper limit of the twist count can be, for example, less than 850TPM, less than 800TPM, less than 750TPM, less than 700TPM, less than 650TPM, less than 600TPM, less than 550TPM, less than 500TPM, less than 450TPM or less than 400TPM.

[0075] Although not particularly limited, the total fineness of the raw cord may be 400 to 9000 dtex. Specifically, in consideration of ensuring mechanical properties, etc., the total fineness of the raw cord may be 1300 dtex or more, 1350 dtex or more, 1400 dtex or more, 1450 dtex or more, 1500 dtex or more, 1550 dtex or more, 1600 dtex or more, 1650 dtex or more, 1750 dtex or more, or 1800 dtex or more, and the upper limit may be, for example, 2000 dtex or less, 1950 dtex or less, 1900 dtex or less, 1850 dtex or less, 1800 dtex or less, 1750 dtex or less, 1700 dtex or less, 1650 dtex or less, or 1600 dtex or less.

[0076] In an exemplary embodiment, the coating layer may be a coating layer formed from the above-mentioned adhesive composition, or may include the above-mentioned adhesive composition. Specifically, the tire cord may be formed by applying the adhesive composition to the original tire cord. There is no particular limitation on the method for applying the adhesive composition. For example, the coating layer may be applied by known dipping or spraying methods.

[0077] According to a specific embodiment of the present application, the rubber reinforcement material (eg, tire cord) in which the above-mentioned adhesive composition is applied to the surface of the original cord may satisfy the color difference value described below.

[0078] In an exemplary embodiment, the coating layer included in the tire cord may include: a first coating layer; and a second coating layer formed on the first coating layer. Specifically, the tire cord may sequentially include an original cord, a first coating layer, and a second coating layer (see Figure 2 ).

[0079] Although not particularly limited, the first coating layer and the second coating layer may have a visually recognizable boundary.

[0080] In an exemplary embodiment, the first coating layer may comprise the same components as the second coating layer.

[0081] In another exemplary embodiment, the first coating may comprise a different component than the second coating.

[0082] Specifically, when the first coating layer and the second coating layer include different components, the first coating layer can be formed by dipping the original cord into a composition (first coating solution) for forming the first coating layer that includes a component that imparts reactive groups. That is, the first coating layer is formed to surround the original cord or its surface. There is no particular restriction on the type of component that imparts reactive groups for the first coating layer, and for example, the first coating solution can include one or more compounds selected from epoxy resins and isocyanates. There is no particular restriction on the solvent component included in the first coating layer forming composition (first coating solution), but considering the compatibility with the second coating layer, a solvent (such as water) identical to the solvent included in the second coating layer forming composition can be included in the first coating layer forming composition. In addition, the second coating layer is formed by dipping the tire cord (or tire cord precursor) formed with the first coating layer on the surface into the second coating layer forming composition (second coating solution), and the second coating layer forming composition (second coating solution) can be identical to the adhesive composition meeting the above-mentioned viscosity.

[0083] In one exemplary embodiment, the first coating solution may include an isocyanate compound and an epoxy compound. In this case, the epoxy compound and the isocyanate compound may be used in a weight ratio of 4:1 to 1:4, 3:1 to 1:3, or 2:1 to 1:2 to achieve sufficient crosslinking and an appropriate level of curing.

[0084] In another exemplary embodiment, the weight of the isocyanate compound in the entire composition may be greater than the weight of the epoxy compound, provided that the content range is satisfied.

[0085] A rubber reinforcing material (eg, tire cord) in which a first coating layer for imparting reactive active groups to the surface of an original cord and a second coating layer including the above-mentioned adhesive are sequentially formed can satisfy the color difference value described below.

[0086] In an exemplary embodiment, the rubber reinforcement material (such as tire cord) has a color difference value L, a and b that meets a predetermined range. Specifically, the tire cord meets the characteristics of L value in the range of 50 to 60, a value in the range of 4.5 to 10 and b value in the range of 10 to 25. The L value refers to the ratio of black to white, the a value refers to the ratio of red to green, and the b value refers to the ratio of yellow to blue. The above-mentioned color difference is due to the color of the adhesive component. Since the fiber used for tire cord generally has a white series, the reinforcement material (such as tire cord) has the same color difference as described above, so that it is possible to simply confirm with the naked eye whether the adhesive composition is evenly coated. The color difference of tire cord can be measured, for example, in the following manner: prepare two cord samples in which a plurality of cord strands are densely arranged in one direction within a predetermined area, and then stack these samples so that the direction in which one sample cord strand is arranged is 90 ° with the direction in which another sample cord strand is arranged. At this time, the number of cords arranged in one direction in a predetermined length (for example, 1 cm) is in the range of 10 to 25, for example, 13 or more or 15 or more, and 22 or less, 20 or less, or 18 or less. The color difference can be measured using a spectrophotometer (CCM, X-rite color-eye7000A).

[0087] In an exemplary embodiment, when the adhesion is evaluated according to ASTM D4393, the adhesion of the cord may be 10 kgf or more. The adhesion may be 15 kgf or more, 15.5 kgf or more, 16 kgf or more, 16.5 kgf or more, or 17 kgf or more. The specific method for measuring the adhesion is as follows. First, a 0.6 mm thick rubber sheet, a cord sheet, a 0.6 mm thick rubber sheet, a cord sheet, and a 0.6 mm thick rubber sheet are sequentially laminated and subjected to a pressure of 60 kg / cm2 at 170°C. 2 The samples were vulcanized under a pressure of 100° C. for 15 minutes to prepare samples. The samples were cut to prepare specimens with a width of 1 inch. The prepared specimens were then subjected to a peel test at a speed of 125 mm / min at 25° C. using a universal testing machine (Instron) in accordance with ASTM D4393, and the adhesion of the cords was measured.

[0088] In another exemplary embodiment of the present application, the present application relates to a method for manufacturing a rubber reinforcement material, wherein the method includes applying a coating liquid to a base material of the rubber reinforcement material to form a coating layer.

[0089] The method of applying the coating liquid to the substrate is not particularly limited, but may be, for example, spraying or dipping, preferably dipping.

[0090] In an exemplary embodiment, the rubber reinforcement material may be tire cord.

[0091] In an exemplary embodiment, the base material may be a fiber base material, specifically, a raw cord. The description of the material for forming the raw cord, etc. is the same as that described above.

[0092] In an exemplary embodiment, the coating liquid may be the above-mentioned adhesive composition.

[0093] In an exemplary embodiment, the method includes: applying a first coating liquid to a substrate of a rubber reinforcement material to form a first coating layer on the substrate; and applying a second coating liquid to the first coating layer to form a second coating layer on the first coating layer.

[0094] The method of applying the first coating liquid onto the substrate or applying the second coating liquid onto the first coating layer is not particularly limited, and for example, may be spraying or dipping, preferably dipping.

[0095] After the coating liquid for forming the first and / or second coating layer is applied, the coating liquid may be dried and / or cured as necessary.

[0096] In an exemplary embodiment, the components of the first coating liquid and the second coating liquid may be the same or different.

[0097] For example, the first coating solution may contain an epoxy compound and an isocyanate compound to impart reactive groups to the fiber base material, etc. In this case, the epoxy compound and the isocyanate compound may be used in a weight ratio of 4:1 to 1:4, 3:1 to 1:3, or 2:1 to 1:2 to allow for sufficient crosslinking and an appropriate level of curing.

[0098] In one exemplary embodiment, the first coating liquid may include a solvent. That is, the first coating liquid may include an epoxy compound, an isocyanate compound, and a solvent.

[0099] When the content of the solvent is insufficient, the first coating by dipping does not proceed smoothly, and when the content of the solvent is too high, the reactive group is not sufficiently imparted to the base material for reinforcing the rubber. Taking these points into consideration, the content of the solvent is 94% to 99% by weight based on the total weight of the first coating liquid, and the content of the mixture of the epoxy compound and the isocyanate compound is 1% to 6% by weight. That is, based on the total weight, the first coating liquid contains 1% to 6% by weight of the mixture consisting of the epoxy compound and the isocyanate compound and 94% to 99% by weight of the solvent. Although not particularly limited, the solvent that can be included or used in the first coating liquid can include the same components as the solvent of the second coating liquid.

[0100] In an exemplary embodiment, the base material for the rubber reinforcement can be immersed in the first coating liquid and then dried. Specifically, the first coating liquid is applied to the base material for the rubber reinforcement by dipping. Then, the first coating liquid can be dried and cured to form a first coating.

[0101] In a specific embodiment of the present application, the first coating liquid applied to the substrate can be dried at a temperature of 100°C to 160°C for 30 to 150 seconds. Furthermore, in a specific embodiment of the present application, after drying, the dried first coating liquid can be cured at a temperature of 200°C to 260°C for 30 to 150 seconds. Through drying and curing, a first coating layer is formed on the substrate for the rubber reinforcement material. Drying and curing under the above conditions can stably form the first coating layer on the substrate for the rubber reinforcement material.

[0102] Although not particularly limited, during the dipping, drying and / or curing process, a tension in the range of 0.05 g / d to 3.00 g / d may be applied to the original cord. However, another embodiment of the present application is not limited thereto, and tension may not be applied to the original cord.

[0103] In an exemplary embodiment, the second coating liquid different from the first coating liquid containing the epoxy compound and the isocyanate compound may be an adhesive composition satisfying the above viscosity. Specifically, the second coating liquid may contain at least a naturally occurring acid, a nitrogen compound, and latex.

[0104] In a specific embodiment according to the present application, the method may further include a step of forming a second coating on the substrate for rubber reinforcement material to which the reactive active group is imparted, that is, on the first coating. The process (e.g., method and conditions) for forming the second coating may be the same or similar to the process for forming the first coating.

[0105] For example, the second coating liquid can be applied to the base material and the first coating to form the second coating. Alternatively, the second coating liquid can be applied to the base material and the first coating layer, and then the second coating liquid can be dried and solidified. The second coating liquid can be applied by dipping, spraying, etc.

[0106] In a specific embodiment of the present application, the second coating liquid can be dried at a temperature of 100°C to 160°C for 30 to 150 seconds. Furthermore, in a specific embodiment of the present application, after drying, the second coating liquid can be cured at a temperature of 200°C to 260°C for 30 to 150 seconds. By drying and curing under the above conditions, a second coating layer can be stably formed on the first coating layer. As a result, a rubber reinforcement material having a coating layer is provided.

[0107] Although not particularly limited, during the dipping, drying and / or curing process, a tension in the range of 0.05 g / d to 3.00 g / d may be applied to the original cord. However, another embodiment of the present application is not limited thereto, and tension may not be applied to the original cord.

[0108] The following will refer to Figure 2 and Figure 3 A method of manufacturing a rubber reinforcement material according to an exemplary embodiment of the present application is described.

[0109] The raw cord 10 may be manufactured and / or distributed in a state of being wound on the first winder 100. Then, the raw cord 10 may be dipped in the first coating liquid 21′ contained in the first coating tank 200 and coated onto the raw cord 10. During the dipping step, the tension, dipping time, and temperature may be appropriately adjusted, which may be appropriately adjusted by those skilled in the art.

[0110] Next, the first coating liquid 21' applied to the original cord 10 may be dried and cured. Drying may be performed in the drying device 300. The conditions such as the temperature and time for drying and curing are as described above.

[0111] Next, a step of forming a second coating layer 22 on the first coating layer 21 is performed. This second coating layer forming step is a step of applying the rubber-based adhesive composition to the raw cord 10 to which the reactive groups are imparted by the first coating layer 21. To form the second coating layer, a second coating liquid having a composition different from that of the first coating liquid can be used, and the dipping step can be applied in the same manner as in the formation of the first coating layer.

[0112] In order to form the second coating layer 22, the original cord 10 coated with the first coating layer 21 is dipped in a second coating liquid 22'. The second coating liquid 22' is contained in a second coating tank 400. The second coating liquid 22' is applied to the first coating layer 21 by dipping. During the dipping step, the tension, dipping time and temperature can be appropriately adjusted, which can be appropriately adjusted by those skilled in the art.

[0113] Then, the second coating liquid 22' is dried and solidified. Drying and solidification can be performed in the drying device 500. The conditions such as the temperature and time of drying and solidification are as described above.

[0114] By the above fixing, the second coating layer 22 is formed on the first coating layer 21. The tire cord 30 manufactured in this manner is wound on the second winder 600.

[0115] The tire cord 30 having the coating layer formed by the above-described dipping may be referred to as a dipped cord.

[0116] In another exemplary embodiment of the present application, the present application relates to an article (or rubber composite material) comprising the rubber reinforced material. The rubber composite material may be, for example, a tire. The tire comprises the tire cord described above.

[0117] The tire may have a generally known construction (eg, whether the tire is a tread, a carcass ply, a belt, a sidewall, a bead, an inner liner, a cap layer or an apex, etc.) except for the tire cord (see Figure 4 ).

[0118] Beneficial effects

[0119] According to one exemplary embodiment of the present application, an adhesive can be provided that is not only less harmful to the human body and environmentally friendly, but also provides convenience in the cord manufacturing process and reduces costs. Furthermore, the present application has the effect of providing an adhesive that provides performance (e.g., adhesion) equal to or greater than that of the prior art. Furthermore, according to another exemplary embodiment of the present application, a rubber-reinforced material (e.g., tire cord) and an article (e.g., tire) manufactured using the adhesive can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0120] Figure 1 An Ubbelohde viscometer is schematically shown in order to illustrate a method for measuring the relative viscosity of the adhesive composition of the present application.

[0121] Figure 2 A cross section of a tire cord that can be manufactured by using the adhesive composition according to an exemplary embodiment of the present application is schematically shown.

[0122] Figure 3 The manufacturing process of tire cord is schematically shown.

[0123] Figure 4 The cross section of a tire is schematically shown, and the tire can be manufactured by using the adhesive composition according to an exemplary embodiment of the present application.

[0124] FIG5 schematically shows the appearance of a sample used for color difference measurement. Specifically, Figure 5a is an exemplary embodiment of a sample (S1 or S2), and Figure 5b A state in which two specimens S1 and S2 intersect is schematically shown.

[0125] Figure 6 This is a graph showing the results of wavelength analysis of naturally occurring tannic acid used in Examples, synthetic tannic acid used in Comparative Example 3, and RF (diphenol) used in Comparative Example 4 according to infrared spectroscopy. In this graph, the curve shown at the top (or left) relates to RF, the curve shown at the bottom (or right) relates to synthetic tannic acid, and the curve shown in the center relates to naturally occurring tannic acid. At approximately 1600 to 1620 cm -1 Peaks observed near the generally defined wavenumbers are those of aromatic rings. RF condensates and tannic acid generally have benzene rings, but RF is known to be hazardous. Tannic acid, on the other hand, is harmless except for direct inhalation of dust. Naturally occurring tannic acid and synthetic tannic acid have been confirmed to have a peak at approximately 1700 cm-1. -1 The presence or absence of a peak near the wave number of 1700cm -1 The peak near the wavenumber of is a peak arising from C=O bonds. This peak is believed to be due to the C=O bonds produced during the synthetic synthesis of tannic acid. This means that synthetic tannic acid differs from naturally occurring tannic acid in that the C=O units in naturally occurring tannic acid are smaller.

[0126] [Explanation of Reference Numerals]

[0127] 10: Original cord

[0128] 11: First twist yarn

[0129] 12: First twist yarn

[0130] 20: Coating

[0131] 21: First coating

[0132] 21′: First coating liquid

[0133] 22: Second coating

[0134] 22′: Second coating liquid

[0135] 30: Tire cord

[0136] 100: First winding machine

[0137] 200: First paint can

[0138] 300: First drying device

[0139] 400: Second paint tank

[0140] 500: Second drying device

[0141] 600: Second winding machine

[0142] 1000: tread

[0143] 2000: Shoulder

[0144] 3000: Sidewall

[0145] 4000: crown layer

[0146] 5000: belt layer

[0147] 6000: carcass cord or carcass

[0148] 7000: Lining

[0149] 8000: Apex

[0150] 9000: Bead DETAILED DESCRIPTION

[0151] Hereinafter, the functions and effects of the present invention will be described in more detail with reference to specific embodiments of the present invention. However, these embodiments are presented for illustrative purposes only, and the scope of the present invention is not limited thereto in any way.

[0152] Preparation of compositions of Examples and Comparative Examples

[0153] The compositions of Examples and Comparative Examples were prepared by mixing and stirring under the same conditions except that the content (wt%) ratios were the same as in the following Table 1. Specifically, the components were mixed and stirred at about 20° C. for 24 hours.

[0154] [Table 1]

[0155]

[0156] Test 1: Measuring the relative viscosity of the compositions of Examples and Comparative Examples

[0157] The adhesive composition having the components shown in Table 1 was placed in a constant temperature water bath (approximately 25°C) for 30 minutes, and then its viscosity was measured using an Ubbelohde viscometer. Specifically, a certain amount of demineralized water was added to the Ubbelohde viscometer using the following method, and the viscosity characteristics of the demineralized water were measured. After measuring the viscosity characteristics of the composition in the same manner, the relative viscosity was calculated based on the previously measured viscosity characteristics of the demineralized water. The results are shown in Table 2.

[0158] The following will refer to Figure 1 Describe the viscosity measurement process.

[0159] (1) Pour the sample (composition or demineralized water) into tube A of the Ubbelohde viscometer.

[0160] (2) Set a constant temperature water bath to 25°C, then fix part C so as to be immersed in the water bath and leave it for 30 minutes.

[0161] (3) Using a pipette, place the sample in the center of part C.

[0162] (4) Thereafter, the sample is allowed to flow downward, and the time required for the liquid surface of the sample to pass through the upper scale mark B and the lower scale mark B is measured.

[0163] (5) Apply the measured time to the following relative viscosity calculation formula to obtain the relative viscosity.

[0164] <Relative viscosity calculation formula>

[0165] Relative viscosity = T1 / T0

[0166] In the above formula, T1 is the time required for the adhesive composition to pass through the upper scale of B and the lower scale of B, and T0 is the time required for demineralized water to pass through the upper scale of B and the lower scale of B.

[0167] [Table 2]

[0168] Relative viscosity Example 1 2.51 Example 2 2.46 Example 3 2.55 Example 4 2.58 Example 5 2.54 Example 6 2.59 Example 7 2.62 Example 8 2.68 Example 9 2.75 Example 10 2.79 Comparative Example 1 2.21 Comparative Example 2 2.04 Comparative Example 3 2.13 Reference Example 1 2.36

[0169] It can be confirmed from Tables 1 and 2 that the viscosity of the adhesive composition varies depending on the components forming the composition and their contents. The components, contents, and viscosity of the adhesive affect color characteristics and adhesive force, as in the tests described below.

[0170] Test 2: Measurement of color difference of dipped cords

[0171] Two ply twisted yarns (Z direction) with a twist count of 360 TPM using polyester yarn were prepared, and then the two ply twisted yarns were secondarily twisted (S direction) with a twist count of 360 TPM to prepare a ply twisted yarn (1650 dtex / 2 ply). The ply twisted yarn thus prepared was used as the original cord 10.

[0172] The polyester raw cord was immersed in a first coating solution and then treated at a drying temperature of 150°C and a curing temperature of 240°C for approximately 1 minute, respectively, to form a first coating layer 21, thereby imparting reactive groups to the cord. The first coating solution was prepared by mixing the epoxy compound and isocyanate compound, which were some of the components used in Preparation Example 2, at a weight ratio of approximately 1:2 with 97% by weight of demineralized water.

[0173] The original cord, having the first coating formed thereon, was then dipped in a second coating liquid (the adhesive composition prepared in the Examples and Comparative Examples), dried, and cured to form a second coating layer 22. Drying and curing were performed at a drying temperature of 150°C and a curing temperature of 235°C for approximately one minute, respectively. The dipping steps for the first and second coating liquids were performed continuously, under a tension of 0.5 g / d. A tire cord 30 was manufactured as a dipped cord by the above method.

[0174] The manufactured tire cord was cut to prepare two square specimens (S1, S2) with a size of 5 cm × 5 cm. Specifically, two specimens (S1, S2) were prepared in which a plurality of cord strands were closely arranged in one direction so that 15 to 16 strands were present per 1 cm. These specimens were then stacked so that the cord arrangement direction of specimen S1 was 90° to the cord arrangement direction of specimen S2. These were used as samples for measuring color difference (see Figure 5a and Figure 5b ).

[0175] The color difference (L, a, b) of each sample was measured 10 times using a spectrophotometer (CCM, X-rite color-eye 7000A), and the arithmetic mean was obtained. The results are shown in Table 3 below.

[0176] [Table 3]

[0177]

[0178]

[0179] It was confirmed that the Examples containing appropriate amounts of naturally occurring tannic acid and other components exhibited the aforementioned L*, a*, and b* values. Specifically, the tire cords according to the Examples had a deep auburn color. On the other hand, it was confirmed that Comparative Examples 1 to 3 generally did not meet the L* value requirements in terms of color difference.

[0180] Specifically, when visually confirmed, Reference Example 1 exhibited a light auburn color, while Examples exhibited a darker auburn color. This was determined to be because Reference Example 1 had generally lower L* and a* values, and generally higher a* values, than Examples.

[0181] Furthermore, in the case of Comparative Examples in which the L and b values ​​are generally lower than those of Examples, a substantially purple color is exhibited.

[0182] Test 3: Evaluation of Adhesion

[0183] The adhesive force per unit area of ​​the tire cord produced in Test 2 was evaluated. The evaluation of the adhesive force was performed by measuring the adhesive peel strength of the tire cord using the method of ASTM D4393.

[0184] Specifically, a 0.6 mm thick rubber sheet, a cord sheet (corresponding to S1, which is one of the samples manufactured in Test 2), a 0.6 mm thick rubber sheet and a cord sheet (corresponding to S1, which is one of the samples manufactured in Test 2), a 0.6 mm thick rubber sheet were sequentially laminated and subjected to a pressure of 60 kg / cm2 at 170°C. 2 Samples were prepared by vulcanizing under a pressure of 100°C for 15 minutes. The samples were then cut to produce test specimens with a width of 1 inch. For reference, a rubber sheet having the composition shown in Table 4 below was used to construct the tire carcass. Using a laminated material using this rubber sheet, the adhesion between the tire cord and the carcass ply was confirmed.

[0185] The prepared specimens were subjected to a peeling test using an Instron at a speed of 125 mm / min at 25° C. to measure the adhesion between the tire cord and the carcass layer, and the relative values ​​of the measured adhesion are shown in the following Table 5. At this time, the average value of three times the load generated during the peeling process was calculated as the adhesion.

[0186] [Table 4]

[0187] Rubber sheet components Content (based on 100 parts by weight of natural rubber) natural rubber 100 zinc oxide 3 carbon black 29.8 stearic acid 2.0 pine tar 7.0 Mercaptobenzothiazole 1.25 sulfur 3.0 diphenylguanidine 0.15 Phenyl β-p-phenylenediamine 1.0

[0188] [Table 5]

[0189]

[0190] From Table 5, it can be confirmed that Examples provide stronger adhesive force than Comparative Examples.

[0191] Furthermore, by comparing Reference Example 2 with the Examples, it can be seen that the present invention not only provides an adhesive force equal to or higher than that of the prior art, but is also less harmful to the human body and is environmentally friendly.

Claims

1. An adhesive composition comprising a naturally occurring acid, a nitrogen compound and a latex, in, The relative viscosity of the adhesive composition measured at room temperature using an Ubbelohde viscometer satisfies the range of 2.30 to 3.00, wherein the naturally occurring acid comprises naturally occurring tannic acid, wherein the nitrogen compound comprises at least one selected from ammonia (NH3), aniline, trimethylamine, methylamine, dimethylamine and ethylamine, Wherein, the latex is VP latex, Wherein, based on 100 parts by weight of the latex, the adhesive composition includes 5 to 50 parts by weight of the naturally occurring acid, and 0.5 to 25 parts by weight of the nitrogen compound.

2. The adhesive composition according to claim 1, The adhesive composition includes 1.0 wt % or more of the naturally occurring acid based on 100 wt % of the total content of the adhesive composition.

3. The adhesive composition according to claim 1, The adhesive composition includes 0.5 wt % or more of the nitrogen compound based on 100 wt % of the total content of the adhesive composition.

4. The adhesive composition according to claim 1, The adhesive composition further comprises a solvent.

5. The adhesive composition according to claim 4, The adhesive composition includes 35 wt % or more of the solvent based on 100 wt % of the total content of the adhesive composition.

6. The adhesive composition according to claim 4, The adhesive composition includes 50 wt % or more of the solvent based on 100 wt % of the total content of the adhesive composition.

7. The adhesive composition according to claim 4 or 5, wherein: The solvent comprises water.

8. A rubber reinforced material comprising: Raw cord containing fibers; and a coating formed on the original cord, Wherein, the coating layer comprises the adhesive composition according to claim 1.

9. The rubber reinforced material according to claim 8, wherein: The raw cord includes at least one selected from polyester fiber, nylon fiber, aramid fiber, carbon fiber, polyketone fiber, cellulose fiber and glass fiber.

10. The rubber reinforced material according to claim 8, wherein: When measured by a colorimeter, the L* value is 50 to 60, the a* value is 4.5 to 10, and the b* value is 10 to 25.

11. The rubber reinforced material according to claim 8, wherein: The rubber reinforcement material is tire cord.

12. An article comprising the rubber reinforced material according to claim 8.

13. The article of claim 12, wherein: The article is a tire.

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